Building structure



April 12, 1938. R. ZOETTL BUILDING STRUCTURE Filed Oct. 21, 1936 4Sheets-Sheet l INVENTOR. fiaierf Zoe/ZZZ,

ATTORNEY.

Patented Apr. 1 2, 1938 UNlTED STATES.

PATENT OFFICE BUILDING STRUCTURE Robert zcem, Salzblll'g, Austria,asslgnor of fourtenths to Hans Knoll, Salzburg, Austria ApplicationOctober 21, 1936, Serial No. 108,856 In Germany Novemberz'l, 1935 14Claims. (01. 12-41) This invention relates to certain new and usefulimprovements in building structures, and parand convenient subdivisionas to length, width and height to produce component parts of suitableshapes and of diflerent dimensions for various uses for which separateand independently formed units have heretofore generally been employedin the construction of ceilings, walls, chimneys, partitions and variousother parts of buildings, whereby the necessity of producing a pluralityof different sizes and forms of individual units for the variouspurposes required in suchbuilding constructions may be avoided.

Another object of the invention is to provide a building block or tilewhich is equally well adapted for the construction of walls and ofceilings such as of the reinforced concrete hollow tile type, and whichnot only may be used as a standard unit but is divisible into all theform pieces generally required in the ordinary erecand in theconstruction of pilasters, ledges, ribs,

window framlngs and for facading purposes.

Still another object of the invention is to provide a multiform,universal or one-type block which is easy to sort, handle or staple,which may be specified by the architect as a single block item for themany andvarious uses of blocks in different forms and sizes required ina building structure, thus doing away with the necessity of thearchitect figuring how many diiferent sizes and types of blocks areneeded for a certain building, which allows the mason or bricklayer toobtain from the master or standard block unit by means of a few deftblows of his hammer or trowel whatever subforms and sizes he 'requires,and which greatly simplifies building operations and secures economy inhandling and using such blocks from manufacture by the pressing machineto the mason or bricklayer in the various intermediate phases.

Still another object of the invention is to provide a six-sided hollowbuilding tile or block which is closed by shell portions on five of itssix sides so as to enableitto be laid without falsework or use of voidclosures and in such manner that mortar or concrete cannot enter thevoids thereof, which is so constructed as to allow full mortaringwithout outside exposure of the mortar, and which is adapted, in aceiling structure, for supporting joint closing plates and for firmanchorage engagement with concrete fillings in a most effective manner.-

Still another object of the invention is to provide a hollow block ortile in which the relative arrangement of the voids and webs is such asto secure the production oi a block or tile of maximum strengtlr, oneadapted to secure a better load distribution than is possible by the useof blocks of ordinary type, and one adapted in ceiling construction tobe laid to'sustain upper or lower pressures, as the case may be, to mostefiectively meet requirements for negative or'positive flexingmovements.

Still another object of the invention is to provide a hollow buildingblock which may be used with other standard building blocks or unitsemployed in wall, ceiling and other building con structions, and whichadapts the laid blocks to be arranged in a staggered order to obtain afirm interlock with concrete fillings, whereby the use of an overlay ofconcrete to secure a secure binding of the blocks is renderedunnecessary.

With these and other objects in view, the invention consists of thefeatures of construction, combination and arrangement of parts,hereinafterfully described and claimed, reference being had to theaccompanying drawings, in which:

Fig. 1 is a bottom perspective view, looking toward one end of the blockor tile, of a building block or tile constructed in accordance with myinvention. v

Fig. 2 is a top perspective of the block or tile looking toward theopposite end thereof.

Fig. 3 is a top plan view of the block.

Figs. 3a and 3b are, respectively, a perspective view similar to Fig. 3,and a cross-section on line lb-Jb of Fig. 3a, showing a modification inthe block structure. a

Fig. 4 is a vertical longitudinal section through the block on line l4of Fig. 3.

Fig. 5 is a horizontal transverse section on line 5-5 of Fig. 4.

Fig. 6 is a vertical transverse section on line 6-6 of Fig. 4.

Fig. 7 is a vertical longitudinal section on the line |'l of Fig. 4.

Figs. 8 to 20, inclusive, are plan views showing the capability ofdivision of the block into its various sub-forms.

Figs. 21 and 22 are perspective views of a joint closing plate or tile.

Fig. 23 is a sectional view of another slightly modified block or tile.

Fig. 24 is a horizontal section through a portion of a ceiling showingone mode of employing blocks of my improved construction therein.

Fig. 25'is a horizontal and Fig. 26 a vertical section through theceiling structure shown in Fig. 24.

Fig. 27 is a view similar to Fig. 24 showing another manner of employingthe blocks in a ceiling structure.

Figs. 28 and 29 are views corresponding to Figs.

7 25 and 26'of the structure shown in Fig. 27.

Fig. 30 is a view similar to Figs. 24 and 27- showing still anotherarrangement of blocks in a ceil ing structure.

Fig. 31 is a sectional view showing still another modified form' ofblock.

Referring now more particularly to the drawings, I designates myimproved hollow building block or tile, which may be made of anysuitable material and which as shown is of six sided type and of oblongrectangular form, said block having top and bottom faces 2 and 3, sidefaces 4 and 5 and end faces 8 and 1, respectively. These terms areemployed for convenience of description and without regard to theposition of the block when used in a building construction, as it willbe understood that the block may be arranged lengthwise in use in eithera horizontal or a vertical position and that what may be regarded as thetop, bottom and sides will accordingly vary in these positions. Theblock as a whole is a building unit which may be made of anydesiredsize, or of a standard size or multiple thereof. '1 do notconfine the invention to any particular sizeor range of sizes.

The block is formed of shell portions comprisfing itsfaces or sides 2,4, 5, 6, and I, said shell portions closing these five sides, the sixthside 3 being partially open and constituting the only open side of theblock. In the block body are formed voids 8, 9, [0,1 I and I2 and websl3, l4, l5, |6, and 1'". The voids. 8 in the example shown are three 'innumber, extend longitudinallyof the block' and are arrangedin parallelrelation to'and in alternatingarrangement with the webs l3 and portionsof the sides 4 andi which are longitudinally coextensive therewith. Thevoids 9, I I), II, and I2 and webs l4, l5, l5, and I! are likewisearrangedinparallelrelationship and alternate in arrangement with respectto each other, adjacent webs being separated by an intervening void, butthese voids and webs are arranged transversely of the block and at rightangles to the voids 8 and webs I3.

The block I, as stated, comprises in its whole or undivided state abuilding unit of oblong rectangular form and of a given standard size,but is divisible for the convenience of the mason or bricklayer into aplurality of sections of I smaller sizes and of the same or differentshapes suitable for the various purposes for which separately formed andindependent blocks or tiles have heretofore customarily been employed.This is obtained by a novel and peculiar construction and arrangement ofportions of the block allowing the block to be readily divided alongcertain lines to produce desired sub-form fractions. All the voids, asshown, open through one side or face only. i. e., the bottom side orbelow the top ofthe block. Formed in the top of the block andintersecting'the upper ends of the voids H and I2 are narrow fractureline slits l8, and I9 extending transversely of the block the majorportion of its width, and in the sides of the block are formed fracturegrooves or kerfs 20 and 2| arranged in alinement with each other andwith said voids and slits. In the top face of the block are also formedL-shaped slits 22 and 23 the main portions of which extend from a pointadjacent the block end 6 to a point in proximity to the slit l8, atwhich latter point the inner ends or short limbs of said slits 22 and 23extend at right angles respectively toward the respective sides 4 and 5of the block. In the end 6 of the block are formed fracture grooves 24and 25 arranged inalinement with the longitudinally extending portionsof the slits 22 and 23. and in the sides 4 and 5 of the block are formedfracture grooves 26 and 21 arranged in alinement with the transverseportions of said equidistantly between the same and the end I of theblock, so that the portions of the body block may be separated intoblock divisions at these points along transverse lines, while the outervoids 8 and the slits 22 and 23 intersecting the same are arranged topermit portions of the block body lyingbetween its transverse center andthe end 6 to be separatedalong longitudinal lines. Each side face 4 and5 of the block is provided on opposite sides of its transverse centerwith mortar receiving recesses 28 and 29, and the ends 6 and l of theblock are formed with similar recesses 30 and 3|. These recesses arearranged to produce at the corners and transverse center of each side ofthe block shoulders 32, the shoulders havingledges 33 on their sidesfacing the grooves 28 and 29. Figs-3a and 317 show a modified form ofblock la inwhich V- 'shaped kerfs 22', 23' are employed in place of theslits 22, 23, whichkerfs intersect at their ends 'the kerfs 26 and 21butare separated from the associated voids 8 by intact wall portionssufflciently thick to prevent undue weakening of the face 2 in theirregions, but sufficiently thin to allow ready fracture of the blockalong the lines short of this side of the block and the onlyperforations in such side of the block are those formed by the narrowslits I8, I9, 22, and 23, which are not wide enough to allow mortar toenter the voids therethrough. This construction allows the open side 3of the block-in building a ceiling or wall to be placed so as to beclosed against the entrance of mortar into the voids against an abutmentwall or the side of another block, all remaining sides of the blockbeing adapted to be mortared without liability of penetration of themortar into the voids of the block. By this means a block-of greaterstrength is provided while at the same time the necessity of usingfalsework orclosures to close exposed voids against the entrance ofmortar thereinto is avoided, thereby reducing time and labor in abuilding operation.

Figs. 8 to 20, inclusive, show the block proper and the many forms inwhich it is divisible to suit all general requirements. In- Fig. 8 thewhole block is shown, which is usable as such as a standard block ormajor unit A. By one or more deft blows of a hammer, trowel or othersuitable tool the workman may clearly separate this block along theprovided fracture lines to produce any of the various major or minorsubforms required. Fig. 9 shows the block divided along the lines 23, 21to form a modified major unit A' having a left hand recess a at one endand at the same time produce a small angular or L-shaped left-handbonding, facing or like block or tile 1). Fig. 10 shows the blockdivided along the lines 22, 28 to produce a major unit A2 having a righthand recess a. at one end and a small angular or L- shaped right-handbonding, facing or like block or tile b'. Fig. 11 shows the blockdivided along the lines 22, 23 to produce a major unit A3 having atongue projection c and right and left corner blocks b, 17'. Figs. 12,13, 14, and 15 show three-quarter block units A4, A5, A6, A1 from whichdivisions have been made according to Figs. 8, 9, 10, and 11, whichthree-quarter form is produced by division of the block along thetransverse fracture lines 18, 28. Figs. 16 to 19, inclusive, show, inFig. 16, two half blocks A8, A8 produced by division of the master blockalong the transverse fracture line 19, 2|, and in Figs. 17, 18, and 19further divisions All), All, Al2, Al3 of the half blocks A8 inaccordance with Figs. 9, 10, and 11. Fig. 20 shows a group division ofthe master block into its. component sections along the fracture linesreferred to. From the foregoing it will be seen that the master blockmay be divided in such manner as to produce with the master block itselfas many as sixteen different sizes and shapes of blocks or tilessuitable, in one size and form or another, for all the various purposesfor which such blocks or tiles are used in ceilings, chimneys, walls,interior partitions and other parts of buildings in which bricks ortiles of this character are generally used. Also it will be seen thateach block section or sub-form obtained as a division from the masterblock is complete in itself, each having one or more voids and webs orshell walls, the arrangement of the voids and webs being such that thewebs in certain divisions form complementary shell walls to maintain thecharacteristic feature of a six-sided corner-shouldered block closedblock element and mortar.

An important feature of my invention resides in the fact that the setsof webs 8 and l3, l5, I6, I], arranged respectively on opposite sides ofthe transverse center of the block, or in the portions divisible intothe half block sections A8, A9,

are disposed at right angles to one another. By this means the strengthof the block as a whole is not only greatly increased, for the reasonthat in the latter, the webs may be relatively arranged 5 to adapt theblocksto be used as upper or lower pressure blocks or for obtainingnegative or positive flexing moments. Another important feature of myinvention is that the grooves 28, 29, 30, and

3| may be of sufilcient depth to provide full mor- 10 taring spaces and,in those grooves provided with the kerfs 20,- 2I, 24, and 28, to securea filling of these kerfs with the mortar and a resulting interlockingaction with the mortar to more firmly bind the block in place. Stillanother important 15 feature of the invention is that in all the mainsub-divisions of the block the construction issuch that block sectionsseparated along the line of a particular void will be similarly groovedor channeled at the separated sides for the reception 20 of the bindingmortar.

The blocks are adapted when used in a ceiling construction to beemployed in conjunction with joint closing or cover plates 34. Theseplates are preferably made of the same material as the 25 blocks, andeach plate 84 is of channeled form and comprises a body portion 35having at opposite sides thereof upstanding flanges 86 provided at theirupper edges with outwardly projecting supporting'shoulders or ledges 31.In the forma- 30 tion of a ceiling one of these plates 34 is disposed soas to close the bottom of the mortar receiving channel or space betweenadjacent rows of blocks or tiles, so as to form a bottom support for theintervening filling or rib of concrete and to lie 35 fiush with theunder-surface of the tiles and give proper continuity to the exposedsurface of the ceiling. when so disposed the shoulders or ledges 31 ofthe joint closing plates rest upon the lower shoulders or ledges 83 onthe opposed sides or Q4 ends of theblocks of adjacent rows. Thedescribed construction of the joint closing plate of a channeled formprovides a pocket or trough '88 on its upper or flanged side for thereception of a portion of the concrete filling. I As shown, the 45 innerfaces of the plate flanges may be undercut, as at 39, so that theconcrete received in the dovetailed pocket or trough so formed willinterlock therewith, thereby holding the plate firmly in positionandgfirmly bound to the juxtaposed rows 50 distance the rows of blocksare designed to be 55 placed in the building structure.

In the block structures above described the block half A8 is shown asprovided with three voids. This number may be increased or diminished byregulation of the widths of the voids. 60

Fig. 23, for example, shows a block lb in which. the block half A8 isprovided with two voids, its structure being otherwise the same asblocks I and la.

Figs. 24 to 30, inclusive, show some of themany 65 and various ways ofemploying the blocks and joint ,closing tiles in ceiling constructions.Figs. 24, 25, and 26 show a ceiling structure 0 in which rows of thefull blocks are horizontally disposed,

or placed lengthwise in a horizontal position, the 70 spaces'betweenadjacent rows being closed by the joint plates and concrete fillings D,which concrete fillings may be suitably reinforced. The blocks in eachrow are also shown as arranged in staggered relationship to each otherand with 75 of -the ceiling structure are more firmly bound togetherwithout the necessary use of a concrete or cement overlay. It will beobserved that the blocks of a row are arranged so that the open sides ofadjacent blocks of each row may abut and be thereby closed againstentrance of mortar or other foreign materials, while at the same timethe narrow slits in the slitted sides of the blocks are closed byadjacent blocks, and it will be obvious that where the end blocks of arow have their open sides facing outwardly these sides will be closed byadjacent abutment or partition walls. In the ceiling structure shown inFigs, 2'7, 28, and 29 the blocks are arranged in an upright position orendwise vertically to produce a ceiling of greater depth. With thisarrangement the grooves in opposed faces of the blocks produceadditional voids in the ceiling between the blocks, but otherwise thisstructure gives the same general results as that disclosed in Figs. 24,25, and 26. Fig. 30 shows a ceiling structure 02 in which the blocks arealso arranged in an upright position, but illustrates how by the use ofthe block formations shown in Figs. 9 and 10 an increased amount ofspace may be obtained between adjacent block rows for the reception of aT-shaped concrete filling D when the use of a greater amount of concreteat any point is found necessary or considered advisable. In all theceiling forms shown the bottoms of the blocks and the joint closingtiles give a finished effect to the ceiling surface and it is onlynecessary to apply a light facing of cement for the purpose of fillingingrooves and kerfs to form a level finished surface at the top or floorline of the structure. The above illustrations in Figs. 23 to 30,inclusive, apply only to ceiling structures, but by the use of theblocks in unitary shape and divisions of the blocks into the subformsshown in Figs. 8 to 20, inclusive, all the particular block or tileforms commonly found necessary may be obtained for building abutment andpartitioning walls and other parts of a building in a ready andexpeditious manner and so as to save time and labor and eifectgreatereconomy in carrying out the building work. I

In the construction of block lc shown in Fig. 31 the voids H and Hamprovided withnarrowed extensions Ha, 12a extending to points near theblock faces 4 and 5, which allows the grooves 20, 2| to be dispensedwith ifdesired, and as shown.

From the foregoing description, taken 'in connection with the drawings,the construction, mode of use and advantages of my improved buildingblock and its applications will be readily understood by those versed inthe art without a further and extended description. Blocks of. thischaracter, in addition to the manifold advantages heretofore stated, maybe manufactured by the use of conventional types of block pressingmachines. While the constructions disclosed for purposes ofexemplification are preferred, it will, of course, be understood thatchanges in the form, proportions, and details of block other than thosestated may be made within the scope of the appended claims, withoutdeparting from the spirit or sacrificing any ofthe advantages of theinvention.

What I claim is: v

1. A building block or tile of oblong rectangular form comprising ashell having side and end walls onstruction of the and provided withvoids and webs and coacting weakened portions forming determined linesof fracture arranged for division of the block on a transverse lineparallel with its ends into half sections and for subdivision of atleast one of said half sections on an angular line arranged partially atright angles to and partially parallel with its ends into a plurality ofsections, each section being of definite form to constitute a buildingunit.

2. A building block or tile comprising a shell of oblong rectangularform having two central transverse webs spaced to form a void andweakened surface portions arranged to form inchoate half sections and toallow ready fracture of the block transversely along the line of thevoid into half sections,v the part of the block forming one of saidinchoate half sections-having spaced transverse walls parallel with thefirst named webs and forming a void and weakened surface portionsallowing of its ready fracture transversely along the line of said voidparallel with the first-named line of separation into sections formingquarters of the full block.

3. A building block or tile of oblong rectangular form comprising ashell having side and end walls and a central void and weakened shellsurfaces in line therewith and relatively arranged to allow readyfracture of the block transversely along the line of the'void into halfsections, one of said half sections having voids and weakened shellsurfaces allowing ready fracture of said half section along longitudinaland transverse lines on opposite sides of its longitudinal center toproduce a central tongue portion and right and left hand corner blockportions.

4. A hollow building block or tile comprising a rectangular shell havingside and end walls and provided with sets of voids and webs arrangedrespectively on opposite sides of its transverse center, the voids andwebs of each set being disposed in parallel relation to each other, theset of voids and webs arranged on one side of the center of the-blockextending in a direction longitudinally of the block and parallel withthe 7 side walls thereof and the set of voids and webs arranged on theother side of the transverse center. of the block extending in adirection transversely of the block and parallel with the end wallsthereof, the latter-namedset of voids and webs including 'a void betweenadjacent transverse webs arranged substantially in line with thetransverse center of the block and dividing the block into twotransversely divisible half sections.

5. A hollow building block or tile comprising a rectangular shell havingside and end walls and provided with sets of voids and webs arrangedrespectively on opposite sides of 'its transverse center, the set ofvoids and webs arranged on one side of the transverse center of theblock extending in a direction longitudinally of the block andparallelwith the side walls thereof and the set of voids and webs arranged onthe other sideof the transverse center of the block extending in adirection transversely of the block and parallel with the end wallsthereof, the block being provided with weakened shell portions arrangedin alinement with voids of each set and providing lines of fracture onwhich the block may be divided into component parts longitudinally ortransversely of the block.

6. A hollow building block or tile comprising a six-sided rectangularshell having sets of voids and webs, respectively arranged on oppositesides of the transverse center of the block, said voids opening at oneend through one side of the shell and all of the voids terminating attheir opposite ends within the plane of the opposite side of theshell,the latter-named side of the shell being provided with slitsnarrower than and communicating with the latter-named ends of some ofthe voids, said slits being of such reduced width as to render the endsof the voids with which they communicate substantially closed againstentrance of mortar.

7. A hollow building block or tile comprising an oblong rectangularshell provided with sets of voids and webs on opposite sides of itstransverse center, said voids opening at one end through one side of theblock and terminating at their opposite ends within the plane of theopposite side of the block, the voids and webs of one set being arrangedsubstantially on one side of the transverse center of the block andextending all in a direction longitudinally of the block and the voidsand webs of the other set being arranged substantially on the oppositeside of the transverse center of the block and extending all in adirection transversely of the block, the sec-. ond-named side of theblock being provided in alinement with voids of each set with slitscommunicating with the ends of the voids terminating adjacent to saidside and being of materially less width than the width of the voids soas to substantially close such ends of the voids against the entrance ofmortar, and kerfs formed in the sides of the block at right angles tothe aforementioned sides in alinement with certain of the voids and saidslits, whereby the block may be fractured along determined lines;transversely and longitudinally of the block into component sectionseach constituting a building element.

8. A hollow building block or tile of oblong rectangular form andcomprising a shell having bottom, top, side and end walls and providedwith a set of voids and webs arranged transversely of the block at oneside of its transverse center and parallel with the end walls and another set of voids and webs arranged longitudinally of the block attheopposite side of its transverse center and parallel with the sidewalls, a particular void of the first-named set being disposed at ornear the transverse center of the block and particular voids of thesecond-named set being disposed one on each side of the longitudinalcenter line of the block and between said line and the respective sidesof the block, said voids opening at one end through the bottom of theblock, and weakened portions in the sides and top of the block in linewith said particular voids along which and said voids the block may bedivided into sections.

9. A hollow building block or tile of oblong rectangular form andcomprising a shell having bottom, top, side and end walls and providedwith a set of voids and webs arranged transversely of the block parallelwith the end walls and another set of voids and webs arrangedlongitudinally of the block and parallel with the side walls, aparticular void of the first-named set being disposed at or near thetransverse center of the block and another particular void of said setbeing disposed between the first-named void and an end of the block, andparticular voids of the second-named set being disposed one on each sideof the longitudinal center line of the block and between said lineandthe respective sides of the block, said voids opening at one endthrough the bottom of the block, and weakened portions in the sides, inone end and in the top of the block respectively in line with saidparticular voids of the first and second-named setsalong which and thealin'ed voids the'block may be divided into sections. I

. 10. A hollow building block or tile of rectangular form having top,bottom, side and end faces and provided between its transverse centerand one of its end faces with a plurality of transversely arranged voidsand webs, said voids opening through the bottom face and extendingtherefrom toward and terminating near the' top face, a particular one ofsaid voids being disposed at or near the transverse center of the blockand another particular void being arranged at a point substantiallyequidistantly between the aforesaid central void and the said end faceof the block, the top face of the block having transverse fracturegrooves or slits of less width than the said particular voids and alinedtherewith and substantially closing the voids at such side against theentrance ofimortar, and the side faces of the block having fracturegrooves in line with the said voids and grooves or slits, whereby theblock may be readily divided along the line of the first-named centraltransverse void into half block sectionsand transversely divided alongthe line of the second-named void into sections forming substantiallyequal divisions of that portion of the block in which said second-namedvoid is formed.

11. A hollow building block or tile of rectangular form and havingparallel top and bottom faces, parallel side faces and parallel endfaces, and provided with a plurality of transversely arranged voids andwebs, said voids opening at one and through the bottom face of the blockand terminating at their upper ends adjacent to but below the top faceof the block, said top face being provided with transverse fractureslits in line with and extending from said face toward the upper ends ofat least some of the voids, said slits being of less width than saidvoids so as to substantially close the same against the entrance ofmortar and said side faces having fracture grooves in line with theslits and voids with which the slits aline, whereby the block may bereadily divided transversely into sections along the line of said voids.

12. A hollow building block or tile of rectangular formand havingparallel top and bottom faces, parallel side faces and parallel endfaces, and provided between its transverse center and one of its endfaces with parallel longitudinal voids, one located on each side of itslongitudinal center and between the same and the adjacent side face, thetop face of the block being provided with similarly arranged fractureslits of less width than the voids and overlying the same and said endand side faces of the block having fracture grooves in longitudinal andtransverse alinement respectively with the outer and inner ends of therespective slits, ,whereby that portion of the block between itstransverse center an intermediate void, arranged between said centervoid and said end of the block, said center and intermediate voids beingspaced to permit transverse fracture of the block along linespredetermined thereby, said block having weakened face portions in linewith said center and intermediate voids to facilitate fracture of theblock along said lines into sections, the arrangement of the webs andvoids being such that in any division of the block each section isformed with at least a single void and at least one of the void formingwebs forms a face of the section.

14. A hollow building block or tile comprising a rectangular shellhaving a set of spaced transverse webs forming transverse voids locatedon one side of its transverse center, and having a set of spacedlongitudinal webs forming longitudinal voids located on the oppositeside of its longitudinal center, the first-named set of voids includinga void arranged substantially at the transverse center of the block anda void arranged substantially midway between the transverse center ofthe block and the outer end of that portion of the block in which saidtransverse set of voids are arranged, and said second or longitudinalset of voids including voids disposed equidistantly on opposite sides ofthe longitudinal center of the block and between its longitudinal centerand the opposite sides of the block, the block shell having externalweakening and fracture line determining portions in its top and sidefaces and in the outer end of that portion of the block in which thelongitudinal voids are formed registering with said particularly locatedtransverse and longitudinal voids whereby the block may be readilyfractured transversely and longitudinally into sections along the linesof said particular voids.

ROBERT ZOE'I'I'L.

